Soyuz-U
A Soyuz-U on the launchpad for the Soyuz 18 mission in 1975 | |
| Function | Medium-lift launch vehicle |
|---|---|
| Manufacturer | TsSKB-Progress |
| Country of origin | Soviet Union · Russia |
| Size | |
| Height |
|
| Diameter | 10.3 m (33 ft 10 in) |
| Mass |
|
| Stages | 3 or 4 |
| Capacity | |
| Payload to LEO | |
| Mass | |
| Associated rockets | |
| Family | R-7 (Soyuz) |
| Based on | |
| Derivative work | Soyuz-U2 · Soyuz-FG |
| Launch history | |
| Status | Retired |
| Launch sites | |
| Total launches |
|
| Success(es) | 765 |
| Failure(s) | 21 |
| Notable outcome(s) | Soyuz T-10a |
| First flight | 18 May 1973 |
| Last flight | 22 February 2017 (Progress MS-05) |
| Carries passengers or cargo | |
| Boosters (First stage) – Block B, V, G & D | |
| No. boosters | 4 |
| Height | 19.6 m (64 ft 4 in) |
| Diameter | 2.68 m (8 ft 10 in) |
| Empty mass | 3,800 kg (8,400 lb) |
| Gross mass | 43,400 kg (95,700 lb) |
| Powered by | 1 × RD-117 |
| Maximum thrust | SL: 838.5 kN (188,500 lbf) vac: 1,021.3 kN (229,600 lbf) |
| Specific impulse | SL: 262 s (2.57 km/s) vac: 319 s (3.13 km/s) |
| Burn time | 118 seconds |
| Propellant | LOX/RG-1 |
| Second stage (core) – Block A | |
| Height | 27.10 m (88 ft 11 in) |
| Diameter | 2.95 m (9 ft 8 in) |
| Empty mass | 6,550 kg (14,440 lb) |
| Gross mass | 99,500 kg (219,400 lb) |
| Powered by | 1 × RD-118 |
| Maximum thrust | SL: 792.5 kN (178,200 lbf) vac: 990.2 kN (222,600 lbf) |
| Specific impulse | SL: 255 s (2.50 km/s) vac: 319 s (3.13 km/s) |
| Burn time | 290 seconds |
| Propellant | LOX/RG-1 |
| Third stage – Block I | |
| Height | 6.70 m (22 ft 0 in) |
| Diameter | 2.66 m (8 ft 9 in) |
| Empty mass | 2,410 kg (5,310 lb) |
| Gross mass | 25,200 kg (55,600 lb) |
| Powered by | 1 × RD-0110 |
| Maximum thrust | 297.9 kN (67,000 lbf) |
| Specific impulse | 325 s (3.19 km/s) |
| Burn time | 270 seconds |
| Propellant | LOX/RG-1 |
| Fourth stage (optional) – Fregat | |
| Height | 1.5 m (4 ft 11 in) |
| Diameter | 3.35 m (11.0 ft) |
| Empty mass | 930 kg (2,050 lb) |
| Propellant mass | 5,250 kg (11,570 lb) |
| Powered by | 1 × S5.92 |
| Maximum thrust | 19.85 kN (4,460 lbf) |
| Specific impulse | 333.2 s (3.268 km/s) |
| Burn time | Up to 1,100 seconds (up to 7 starts) |
| Propellant | N2O4 / UDMH |
| Fourth stage (optional) – Ikar | |
| Height | 2.56 m (8 ft 5 in) |
| Diameter | 2.72 m (8 ft 11 in) |
| Empty mass | 820 kg (1,810 lb) |
| Gross mass | 3,164 kg (6,975 lb) |
| Propellant mass | 2,310 kg (5,090 lb) |
| Powered by | 1 × S5.144 |
| Maximum thrust | 2.943 kN (662 lbf) |
| Specific impulse | 326 s (3.20 km/s) |
| Burn time | Up to 600 seconds (up to 50 starts) |
| Propellant | N2O4 / UDMH |
Soyuz-U (GRAU index: 11A511U) was a Soviet and later Russian expendable medium-lift launch vehicle designed by the TsSKB design bureau and constructed at the Progress factory in Samara, Russia. The U designation stands for unified, as the launch vehicle was the replacement for both the Voskhod rocket and the original Soyuz rocket. The Soyuz-U is part of the R-7 rocket family, which evolved from the R-7 Semyorka, an intercontinental ballistic missile.
The first Soyuz-U flight took place on 18 May 1973, carrying as its payload Kosmos 559, a Zenit military surveillance satellite. The final flight of a Soyuz-U rocket took place on 22 February 2017, carrying Progress MS-05 to the International Space Station.
Soyuz-U was in use continuously for almost 44 years. Production of R-7 derived launch vehicles peaked in the late 1970s-early 1980s at 55–60 a year. Soyuz-U held the world record of highest launch rate in a year in 1979 with 47 flights until this was beaten by SpaceX's Falcon 9 in 2022. Over its operational lifetime, the Soyuz-U variant flew a total of 786 missions, another world record. Soyuz-U has also been one of the most reliable launchers, with a success rate of 97.3%.